The gemstone associated with the month of August is Peridot, a vibrant green variety of the mineral olivine. Renowned for its distinctive olive to lime-green hue, peridot has captivated civilizations for millennia, earning titles such as the "Evening Emerald" and the "Gem of the Sun." As a birthstone, it symbolizes strength, prosperity, and protection. This article delves into the geological origins, historical significance, gemological properties, and care of this remarkable gemstone, drawing exclusively from the provided source materials.
Peridot's unique color stems from its iron content, a defining characteristic that sets it apart from other green gems like emerald. Unlike many gemstones that derive their color from trace impurities, peridot's hue is an intrinsic property of its chemical composition. This consistency makes it a favorite among jewelers and collectors seeking reliable color saturation. The gemstone's history is deeply intertwined with ancient cultures, particularly in Egypt, where it was mined on the island of Zabargad (St. John’s Island) in the Red Sea. Historical records indicate that peridot was prized by the ancient Egyptians, who believed it possessed protective powers and was associated with the sun god Ra.
The journey of peridot to modern birthstone lists is a story of cultural evolution. While its historical use is ancient, its formal designation as an August birthstone is a more recent development, reflecting changes in societal values and the gemstone trade. Today, peridot is celebrated not only for its beauty but also for its accessibility, with significant deposits found in various parts of the world, including Arizona, Myanmar, and Pakistan.
This article will explore the multifaceted nature of peridot, beginning with its historical and cultural journey, followed by an examination of its geological formation and global sources. A detailed section on gemological properties will provide the scientific framework for understanding peridot's physical characteristics. The discussion will then shift to the symbolism and metaphysical beliefs that have surrounded the stone throughout history. Finally, practical advice on care and cleaning will ensure that owners can preserve the gem's brilliance for generations. Through this comprehensive analysis, we aim to provide gemstone enthusiasts, jewelry buyers, and students of gemology with a thorough understanding of peridot, the August birthstone.
History and Lore
Peridot's history is as rich and deep as its color. The gemstone's earliest documented use dates back to the ancient Egyptians, who mined it on the island of Zabargad in the Red Sea. This island, known for its peridot deposits, was a significant source of the gem in antiquity. The Egyptians referred to peridot as the "gem of the sun," believing it offered protection against evil spirits and nightmares. It was often set in gold and worn as an amulet. Historical accounts suggest that peridot was one of the favorite gems of Cleopatra, the last active ruler of the Ptolemaic Kingdom of Egypt. While Cleopatra is famously associated with emeralds, some historians believe that the "emeralds" in her collection were actually peridots, as large, fine-quality emeralds were not available in Egypt at that time, whereas peridot was locally sourced.
The Crusaders transported peridot from Egypt to Europe in the Middle Ages, where it was used to adorn churches and religious artifacts. One of the most famous examples is the "Pala d'Oro," a golden altarpiece in St. Mark's Basilica in Venice, which features peridot alongside other precious stones. However, during this period, peridot was often mistaken for emerald due to the similarity in color, leading to some confusion in historical records. It wasn't until the 18th century that peridot was correctly identified as a distinct mineral species, olivine.
The gemstone's journey to becoming a modern birthstone is a product of the 20th-century standardization of birthstone lists. In 1912, the National Association of Jewelers (now Jewelers of America) in the United States published an official list of birthstones. Peridot was designated as the birthstone for August, alongside sardonyx. This list has been updated over the years, but peridot has remained a constant for August. The inclusion of peridot reflects its growing popularity and the desire for a unique, vibrant gem to represent the summer month.
Peridot's lore extends beyond ancient Egypt. In Hawaiian culture, peridot is associated with the goddess Pele, the goddess of volcanoes and fire. Legend says that peridot crystals are the tears of Pele, which were carried to the ocean by lava flows and later washed ashore. This connection to volcanic activity is geologically accurate, as peridot is often found in volcanic regions. In medieval Europe, peridot was believed to have healing properties, particularly for the eyes. It was thought to improve vision and protect against eye diseases. These beliefs, though not scientifically proven, highlight the gem's long-standing association with health and well-being.
Geological Formation and Sources
Peridot is a magnesium iron silicate with the chemical formula (Mg, Fe)₂SiO₄. It forms deep within the Earth's mantle under high temperatures and pressures. Unlike many gemstones that crystallize in the Earth's crust, peridot is brought to the surface through volcanic activity. It is commonly found in peridotite, a coarse-grained igneous rock, and in basaltic lavas. The gemstone's formation requires specific conditions: a high magnesium-to-iron ratio and the presence of silica. When these elements combine under the right conditions, olivine crystals are formed.
The most famous historical source of peridot is the island of Zabargad (St. John’s Island) in the Red Sea. This island has been mined for peridot for over 3,500 years. The ancient Egyptians extracted peridot from this location, and it remained a significant source until the early 20th century. However, mining on Zabargad was challenging due to the harsh environment and limited resources. Today, the island's peridot deposits are largely depleted, and it is no longer a major commercial source.
Modern peridot mining occurs in several locations worldwide. The United States is a notable producer, with significant deposits in Arizona, particularly in the San Carlos Apache Reservation. Arizona peridot is known for its vibrant olive-green color and is often found in volcanic rock. Other U.S. sources include Hawaii and New Mexico. In Hawaii, peridot is sometimes found as beach stones, washed ashore from volcanic activity.
Other major sources include Myanmar (Burma), which produces peridot of exceptional quality. Burmese peridot is often characterized by its rich, deep green color. Pakistan, specifically the Kohistan region, is another important source. Peridot from Pakistan is known for its large crystal sizes and good clarity. China also has peridot deposits, particularly in the Xinjiang region. Australian peridot, from the state of Queensland, is another source, though it is less common in the global market.
The geological formation of peridot is closely tied to tectonic activity. It is often found in ophiolite complexes, which are sections of the oceanic crust and upper mantle thrust onto continents. These complexes provide a direct window into the Earth's mantle and are a key source of gem-quality peridot. The gemstone's occurrence in volcanic rocks means that it is often mined from open-pit mines or alluvial deposits, where weathering has concentrated the crystals.
Gemological Properties
Peridot possesses a unique set of gemological properties that distinguish it from other green gemstones. Understanding these characteristics is essential for identification, valuation, and care.
Color: The most defining feature of peridot is its color, which ranges from yellowish-green to olive-green. The hue is due to the presence of iron in its chemical structure. Unlike emeralds, which get their color from chromium or vanadium, peridot's color is consistent and does not vary significantly with light source. The most prized color is a rich, pure green with no brown or yellow undertones.
Hardness and Durability: On the Mohs scale of mineral hardness, peridot ranks between 6.5 and 7. This makes it relatively durable but softer than sapphire or diamond (both at 10). While it is suitable for everyday jewelry like rings and earrings, it requires care to avoid scratches and abrasions. Peridot has no cleavage, which is a significant advantage, but it has poor toughness due to its conchoidal fracture. This means it can break or chip if struck with sufficient force.
Crystal System and Specific Gravity: Peridot crystallizes in the orthorhombic system. Its specific gravity (density) ranges from 3.22 to 3.35, which is relatively high and helps in distinguishing it from other gems like quartz (specific gravity 2.65). The refractive index of peridot is between 1.65 and 1.69, and it is singly refractive, meaning light does not split into two rays as it passes through the stone.
Clarity and Inclusions: Peridot is typically found with inclusions, which are internal features that can affect its clarity. Common inclusions include small, needle-like crystals (often called "lily pads") and fluid inclusions. While some inclusions are acceptable and can even be used to identify natural peridot, large or distracting inclusions can reduce the stone's value. Eye-clean peridot, which has no visible inclusions to the naked eye, is highly valued.
Cut and Carat Weight: Peridot is often cut into standard shapes like rounds, ovals, and cushions to maximize its color and brilliance. The gem's color is uniform throughout the crystal, allowing for a wide variety of cuts. Larger peridot crystals are available compared to many other gemstones, so stones over 10 carats are not uncommon. However, the value per carat increases significantly with size, especially for high-quality material.
Chemical Composition and Stability: Peridot's chemical formula, (Mg, Fe)₂SiO₄, indicates that it is a solid solution series between forsterite (Mg-rich) and fayalite (Fe-rich). The gemstone is generally stable under normal conditions but can be affected by heat and chemicals. It should not be exposed to sudden temperature changes or harsh acids, which can damage its surface.
Summary of Gemological Properties
| Property | Value/Range |
|---|---|
| Chemical Formula | (Mg, Fe)₂SiO₄ |
| Crystal System | Orthorhombic |
| Hardness (Mohs) | 6.5 - 7 |
| Specific Gravity | 3.22 - 3.35 |
| Refractive Index | 1.65 - 1.69 |
| Color | Yellowish-green to olive-green |
| Cleavage | None |
| Toughness | Poor to fair |
Symbolism and Metaphysical Beliefs
Peridot has been attributed with a wide range of symbolic meanings and metaphysical properties throughout history. These beliefs, while not scientifically validated, reflect the gemstone's cultural significance and enduring appeal.
In ancient Egypt, peridot was considered a stone of the sun, symbolizing light, warmth, and life. It was believed to ward off evil spirits and protect the wearer from harm. The Egyptians also associated peridot with fertility and rebirth, making it a popular choice for amulets and jewelry worn by royalty and priests. The gemstone's connection to the sun god Ra reinforced its status as a protective and empowering stone.
Medieval Europeans believed that peridot had healing properties, particularly for the eyes. It was thought to improve vision and alleviate eye strain. Some legends claimed that placing peridot under the tongue could relieve thirst, a belief that may have originated from its association with water in Hawaiian culture. In Hawaiian tradition, peridot is linked to the goddess Pele and is believed to bring good fortune and protect against volcanic hazards.
Peridot is also associated with emotional healing and personal growth. Modern metaphysical beliefs suggest that peridot can help release negative emotions, such as jealousy, anger, and stress, and promote feelings of peace and contentment. It is often called the "stone of compassion" and is believed to foster understanding and empathy in relationships. Some practitioners of crystal healing use peridot to balance the heart chakra, encouraging love and forgiveness.
In astrology, peridot is linked to the zodiac sign Leo, though it is officially the birthstone for August. Leos are known for their confidence, creativity, and leadership qualities, and peridot is thought to enhance these traits while providing protection against negativity. The gemstone's vibrant green color is also associated with growth, renewal, and prosperity, making it a popular choice for those seeking to attract abundance and success.
While these metaphysical beliefs are not part of formal gemology, they contribute to peridot's allure and cultural resonance. For many, wearing peridot is not just an aesthetic choice but a connection to ancient traditions and personal intentions.
Care and Cleaning
Proper care is essential to maintain the beauty and longevity of peridot jewelry. Given its moderate hardness and poor toughness, peridot requires careful handling to avoid damage.
Cleaning: Peridot can be cleaned using warm, soapy water and a soft brush. Avoid using ultrasonic cleaners, as the vibrations can cause fractures in the stone, especially if it has existing inclusions. Steam cleaners are also not recommended due to the risk of thermal shock. After cleaning, rinse the gemstone thoroughly to remove any soap residue and dry it with a soft, lint-free cloth.
Storage: Store peridot jewelry separately from other gems and metals to prevent scratches. A soft pouch or a compartmentalized jewelry box is ideal. Avoid storing peridot in direct sunlight for prolonged periods, as some sources suggest that intense heat and light may cause fading, though this is not a significant concern for most peridot varieties.
Avoiding Chemicals: Keep peridot away from harsh chemicals, including household cleaners, cosmetics, and hairsprays. These substances can erode the stone's surface or affect its polish. When applying beauty products, it is advisable to remove peridot jewelry first.
Handling: Remove peridot rings, bracelets, and other jewelry during activities that could subject the stone to impact or abrasion, such as gardening, sports, or manual work. While peridot is durable enough for everyday wear, it is not indestructible. A sudden blow can chip or crack the stone, particularly at the girdle or facet edges.
Professional Maintenance: Periodically, have peridot jewelry inspected by a professional jeweler. The jeweler can check for loose settings, worn prongs, and other issues that could lead to stone loss or damage. Re-polishing may be necessary if the surface becomes scratched over time, but this should be done by an expert to avoid altering the stone's shape or proportions.
By following these care guidelines, owners can ensure that their peridot jewelry remains vibrant and beautiful for generations. The gemstone's durability, combined with proper maintenance, makes it a practical and cherished choice for birthstone jewelry.
Conclusion
Peridot, the August birthstone, is a gem of remarkable beauty and historical depth. From its origins in the Earth's mantle to its journey through ancient civilizations, it has been revered for its vibrant green color and symbolic significance. As a variety of olivine, peridot possesses unique gemological properties that distinguish it from other green gemstones, including its consistent color, moderate hardness, and lack of cleavage. Major sources today include Arizona, Myanmar, Pakistan, and China, ensuring its availability for jewelry enthusiasts worldwide.
The gemstone's lore is rich with associations of protection, healing, and prosperity, reflecting its enduring cultural impact. Whether valued for its metaphysical properties or its aesthetic appeal, peridot remains a popular choice for jewelry, particularly for those born in August. Proper care, including gentle cleaning and safe storage, is essential to preserve its brilliance. In summary, peridot stands as a testament to the enduring allure of gemstones, combining scientific intrigue with a legacy of human fascination.